Please refer to FIG. 9, it is a conventional chain tool comprising a base body 91 and a groove 911. A blocking wall 912 is disposed in the groove 911, and the blocking wall 912 includes a hole 913. A screw rod 92 is locked and fixed to the base body 91. If a chain 93 is broken and is required to be replaced, a roller (not shown) set on the chain 93 is aligned with the hole 913 to dispose in the groove 911, and a chain pin (not shown) is aligned with the axle center of screw rod 92. Since the chain 93 is blocked by the blocking wall 912 and a leaning portion 914, the chain 93 is rotated by driving the screw rod 92. A top rod 921 moves and pushes said chain pin to make it extend or insert into the chain 93.
However, when the chain 93 is set into the groove 911, the roller is aligned with the hole 913, the blocking wall 912 and the leaning portion 914 are used to facilitate the chain 93 to be positioned, but the height of the blocking wall 912 is lower than that of the chain 93 so that the blocking wall 912 is unable to totally block the chain 93. Furthermore, when the top rod 921 pushes the chain pin, in order to avoid the top rod 921 being not aligned with the axle center of chain pin, the hand should press on the chain 93 to make the top rod 921 align with the axle center of chain pin. In addition, when the top rod 921 is rotated to push said chain pin, the chain 93 is blocked by the blocking wall 912. If the strength of blocking wall 912 is not strong enough, the blocking wall 912 will be deformed.
Thus, the most important of the present disclosure is that how to use the conventional chain tool to overcome the problem of said chain pin being incapable of aligning with the top rod 921. The above information disclosed in this section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.